ML20135C846
| ML20135C846 | |
| Person / Time | |
|---|---|
| Site: | Yankee Rowe |
| Issue date: | 12/31/1996 |
| From: | YANKEE ATOMIC ELECTRIC CO. |
| To: | |
| Shared Package | |
| ML20135C840 | List: |
| References | |
| NUDOCS 9703040339 | |
| Download: ML20135C846 (11) | |
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YANKEE ATOMIC ELECTRIC COMPANY YANKEE NUCLEAR POWER STATION (DOCKET NO 50-29) 1996 ANNUAL REPORT I
d 9703040339 970228 !
gDR ADOCK 05000029 PDR i
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1996 ANNUAL REPORT l i
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TABLE OF CONTENTS !
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TITLE PAGE l Introduction.. ... . . . . . .. . . . . . . . . . . . . . . . . . . . i !
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A. Engineering Design Changes.. ... . . . . . . . . . . . . . . . . 1
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B. Decommissioning Work Packages (DWP's).. . . . . 2 l,
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C. Temporary Design Changes.. . . . . . . . . . . . . . . . . 7 ;
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D. NNS Chanps.... . . . .. . .. . . . . . . . . . 7 ,
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t E. Other Changes........ . .. . . . ... . . . . . . . 8 i t
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INTRODUCTION !
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- The Yankee Nuclear Power Station has been shutdown since October 1,1991, and the reactor }
defueled since February 15,1992. The plant has been operating under a Possession Only License l (POL) since August 5,1992. The Decommissioning Plan for the facility was submitted to the _
l Nuclear Regulatory Commission (NRC) on December 20,1993. Followingits review by the NRC !
Staff, the Decommissioning Plan was approved in February 1995. However, in October 1995, l NRC issued CLI 95-14 revoking its approval and prohibited YAEC from conducting further major j decommissioning activities pending approval of the decommissioning plan after completion of the hearing process. By Order dated October 18,1996 (CLI 96-9), in the hearmg process convened to i determine whether an order approving the decommissioning plan for YNPS should be approved, the Commission granted YAEC's Summary Disposition and re-approved the plan. This Order, in accordance with the amended decommissioning regulations in 10CFR50.82, considers this plan to ;
be the Post Shutdown Decommissioning Activities Report (PSDAR).
This report is submitted in accordance with 10CFR50.59(b)(2) and the YNPS Defueled Technical !
Specification 6.8.1. The changes identified in this report nave been resiewed for, and were j determined not to constitute, an unreviewed safety question as described in 10CFR50.59(a)(2). l t
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l A. Enaineerina Desian Chanqes (EDCs) ;
I a EDC 95-302 Reactor Pressure Vessel (RPV) Removal l This EDC covers the removal and packaging of the RPV, as well as the site modifications required ,
to remove the RPV. Final preparation of the RPV head transport package was also contained I within the scope of this EDC.
I RPV removal proceeded in the reverse order in which the RPV was installed. The Upper Neutron '
Shield Tank (UNST) was removed down to the reactor support ring, exposing both the RC piping !
and the upper insulation about the RPV and piping. The insulation, which contains asbestos, was I removed as well as the RC piping between the RPV nozzles and the Reactor Suppon Structure '
interior wall. Steel shield plugs were placed in the exposed RPV nozzles and the exposed RC piping capped. The support pin retainer plates on the suppon lugs were removed.
When the RPV was drained, dross within the RPV was solidified in a liner located within the RPV.
The top cover of the cask was used as the lifting fixture for the RPV. The cover was attached to the RPV by modified head studs using the RPV flange existing stud holes. The RPV was then lifled from the Shield Tank Cavity by the Polar Crane and placed within a cask which was placed below the VC equipment hatch. Once in the cask, the cask cover was welded in place and concrete placed within the RPV and between the RPV and the cask to fix any loose contamination, and to provide shielding. After the concrete cured, the cask was downended to a horizontal position and moved to a location for interim storage and preparation for transport for off-site disposal. The cask has been certified by the NRC for off-site transport as a Type A exclusive use package. It will be transported by heavy roadway hauler to the Hoosac Tmmel rail site in the Spring of 1997.
The intact Reactor Pressure Vessel Removal was evaluated in the FSAR (Section 403.1). The results are that in the bounding case of the non-mechanistic release of all of the RPV radioactive surface contamination directly to the atmosphere outside the vapor container, the EPA PAGs would not be exceeded at their lower limits.
- EDC/95-304 Main Coolant System Decontamination This design change performed a chemical decontamination of the Main Coolant System piping, valves, and pump volutes, Feed and Bleed Heat Exchangers, and minor portions of the Charging, Bleed and Safety injection piping. The decontamination removed approximately 30 curies from these components. This significantly reduced the dose incurred in subsequent loop area work including main coolant piping asbestos insulation removal and main coolant piping and the loop areas component removal. This EDC covered decontamination of the piping and components as well as minor modifications to the Main Coolant System volute covers.
The decontamination process consisted of a combination of chemical solvents which were pumped through the piping and components by a modular decontamination skid or equivalent supplied by the vendor.
This EDC reduced the radiation dose rates within the MCS pipework and components. A significant dose rate reduction lowers personnel exposure during subsequent removal of the main coolant system equipment (MCS piping asbestos, MCS piping, valves, feed and bleed heat exchangers, etc.) and reduced the waste costs associated with disposal of the main coolant piping and components.
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The impact to operations as a result of performing the chemical decontanunation was minimal.
. The pipework and components decontaminated, m physically separated from all operating systems and are no longer required for plant operation.
- EDC 96-303 Temporary Waste Water Processing Island His EDC installed a temporary waste water system to accept and process the remaining waste water generated at YNPS until the end of decommissioning activities.
The new waste water system provided a methodology for the waste water, processing the waste water into concentrated bottoms and clean distillate and discharging the resultant bottoms and distillate. All major equipment, with the exception of the propane tanks, were located in the area adjacent to the Fuel Oil Storage Tank carth berm and Hose House 15. The propane storage tanks were located adjacent to the warehouse. He new system was classified as Non-Nuclear Safety Related (NNS).
The total integrated amount of radioactive material to be processed by the temporary waste water evaporator System is estimated to be minimal, on the order of I Curie. This significantly reduces the radiological consequence of any event, including explosions or seismic events, involving the system because of the amount of radioactive material capable of being released at anytime is minimal and precludes exceeding limits for both liquid and airborne releases. The low level of risk presented by the operation of the system is maintained by administratively controlling the radioactive content of the temporary waste water evaporator system.
B. Decommissionina Work Packanes (DWPs)
Activities, performed via a DWP, including consequences of potential events, are bounded by the decontamination, dismantlement, packaging events, storage events and material handling events in Section 403 of the FSAR. The following specific activities identified by the DWP have met the procedure safety review screenings criteria requirements and did not require a change to the Defueled Technical Specifications or the FSAR.
- DWP/lXP-02 Ion Exchange Pit This DWP covered decontamination, removal and partial dismantlement of portions of the internal and external surfaces of the lon Exchange Pit (IXP) and Pipe Tunnel (PT).
The Ion Exchange Pit is a reinforced concrete structure that previously contained ion exchange capsules, filter vessels and associated equipment used to purify the Main Coolant, Shield Tank Cavity and Spent Fuel Pit water. The IXP and associated PT have both been permanently removed from service.
- DWP/MS-02 Removal of Main Steam Feedwater and other Equipment The piping, components, and supports removed are in the yard between the Vapor Container (VC),
the Turbine Building (TB), the Safety injection Building (SIB) and the Primary Auxiliary Building (PAB). The following systems were removed by this DWP:
- Main Steam System
- Feedwater System
- Fuel Oil System
- Breathing Air Tank (Abandoned in Place) 2 )
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- Steam Gener: tor Blowdown Synem I
. - Secondary Vent Stack !
- licating System
- Primary Plant Vent and Drain System The equipment removed and identified in this DWP provided various functions during plant operation. With the shutdown of the plant, this equipment has no functional requirements.
Therefore, the equipment identified in the scope of this DWP is classified as Non-Nuclear Safety.
l The equipment removed by this DWP is not required to support safe storage of spent fuel, future i dismantlement, or safe storage of those portions of the facility that remain.
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DWP/PABA-01 Pri. nary Auxiliary Building Tank Removal ;
This DWP covered the removal of the following four tanks:
Gravity Drain Tank located in the cubicle corridor located in the Primary Auxiliary Building (PAB). l
. Low Pressure Surge Tank located on the upper level of the PAB. '
. Primary Drain Collecting Tank located in the cubicle corridor of the PAB.
. Vapor Container Drain Tank located in cubicle corridor of the PAB.
Additionally, out-of-service piping, equipment and/or other components located in the PAB Cubicle Corridor area are also included in the scope of this DWP.
The aforementioned tanks have been cut into manageable sections and dismantled (with the l
exception of the Vapor Container Drain Tank). l The tanks, piping and components identified in this DWP for removal prcvided various ftmetions during plant operation. The Gravity Drain Tank was used to collect radioactive liquids from floor !
drains in the PAB and from drains located in the Vapor Container (VC). The Low Pressure Surge l Tank was used to provide surge capacity in the Charging and Volume Control System. The Vapor !
Container Drain Tank receives radioactive liquids that drain from the Vapor Container (VC). The l Primary Drain Collecting Tank was used to collect liquids from the primary plant valve stem leak-offs and the nutin loop drains.
The requirement for the aforementioned tanks and pipework is no longer necessary with permanent cessation of power generation and with fuel pemunently removed from the reactor. The tanks, ;
pipework and components identified in the scope of this DWP are classified as Non-Nuclear Safety.
- DWP/PABA-02 Primary Auxiliary Building-Electrical Component Removals This DWP covers the removal of electrical components located in the Primary Auxiliary Building (mainly MCC4 and its cable runs to either their corresponding PAB electrical component locales, or up to the PAB wall penetration). If the cable runs to loads were within the PAB, both the complete cable run and its load terminations were removed.
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- DWP/PABA-03 Primary Auxili:ry B:ildi;g-Mechanical / Electrical Ccmponent Rem:vals 1
This DWP covers the removal of the remaming mechanical, electrical and piping components located in the Primary Auxiliary Building including the Upper Pipe Chase and Gas Bottle Room Areas.
The following is a list of the major components that have been removed by this DWP in the PAB Building. In addition, all remaining components including electrical raceway, cables, termination boxes / junction boxes, and associated supports have been included in this DWP.
- 1. Normal Lighting and Power Outlets !
- 2. Gaitronics and Sound-Powered Phones '
- 3. Security System
- 4. Fire Detection System
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5 "Through" cables and conduits from other power source / load locales j
- 6. Heating Units j
- 7. All PAB Motor and Pump cables / conduits
- 8. Emergency Lighting .
- 9. Radiation Monitors including: I
- PAB Valve Room
- PAB Cubicle corridor
- Test Tank Efiluent
- Evap Cooling Water The function of these systems were augmented or supplemented by the modifications / enhancements defined in this DWP. All of the systems and equipment associated with this DWP are classified as NNS.
This DWP removed the hydrogen and CO2 storage racks, piping, instrumentation, electrical components, wiring, and conduit located in the Upper Level and Lower Level of the Primary Auxiliary Building, Non-Radioactive Pipe Chase and the Vent C ack House Addition.
The following systems were removed by this DWP.
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- Portions cf Hydrogen Supply Line to Turbine Building,
- Portions of Vapor Container Air Charge Line,
- Portions of Post Accident Hydrogen Vent System,
- Portions of Monitoring Air These systems are not required to support plant operations during the safe storage and dismantlement periods.
The equipment removed and identified in this DWP provided various functions during plant operation. With the shutdown of the plant, this equipment has no functional requirements.
The equipment identified in the scope of this DWP was classified as Non-Nucicar Safety.
- DWP/PABA-06 North Wall Structural Steel Frame & Conduit Removal PAB West Wall Structural Steel Removal The scope of DWP PABA-06 was separated into two parts:
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- 1. The removal of the Primary Auxiliary Building's (PAB) external North Wall, both
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sides of the West Wall, structural steel framing, miscellaneous structural components, the Upper Pipe Chase Tunnel external steel framing.
- 2. The removal of the PAB and Safety injection Building's (SIB) North Wall extemalelectrical cabling, conduit and associated mounting hardware.
- DWP/SIBA-01 Safety Injection Building-Mechanical This DWP removed all of the remaining mechanical components from the Safety Injection (SI)
Building.
His DWP removed the mechanical service systems in the Safety Injection Building including parts of the Fire Water System, parts of the ventilation system, fuel oil piping, sump pumps, compressed air lines, heating steam, and the manhole #3 cardox system. This DWP also removed structural steel reinforcements for the block walls in the Accumulator Tank Room and EDG Cubicle #3 in order to provide access for future decontamination of the walls.
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- DWP/SIBA-02 Station Battery Realignment and Removal of Battery #'s 2,3 and j Associated Equipment This DWP covered the realignment of the Station Battery system. Batteries 1,2 and associated l equipment were located in the Turbine Building Switchgear Room. Battery No. 3 and associated equipment were located in the Emergency Diesel Generator Building (SI Building).
This modification affected the electrical system which was classified NNS, did not affect the physical integrity of the Spent Fuel Pool, did not require Technical Specification changes, and did not adversely impact the safety of the plant in the permanent shutdown and defueled mode.
- DWP/SIBA-03 Safety Injection Building - Electrical Component Removals This DWP covers the removal of electrical components located in the Safety Injection Building.
The following is a list of the major system components which was removed by this DWP in the ;
Safety injection Building (inclusive of the following: SI Room, Accumulator Room, Emergency !
Diesel Generator Rooms (#1, #2 & #3), PICS Room, and Battery Room #3) In addition, all j remaining components including electrical raceway, cable, panels, electrical boxes, and associated supports were included in this DWP.
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- Fire Protection System (including Fire Detection)
- Gaitronics System (including the Plant Evacuation Alarm System) l Sound Powered Phone System e i C System
. V:atilation System i e Annunciator System e SI System
. Area Radiation Monitoring
- Process Radiation Monitoring
= Integrated Leak Rate Temperature e Vibration Monitoring for HPSI, LPSI and EBF Pumps e Security System for Waste Disposal Building (inactive) e Remaining Emergency Diesel Generator Components and Circuits 5
o- Analog Instrument Loop Circuits for Instrument Transmitters located in ; 2 Primary Auxiliary
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- Water Cleanup System
- DWP/VCA-02 VC Systems Outside Bioshield This DWP covers the determination of cables associated in the VC, except for those cables which are required to support decommissioning activities within the VC.
This DWP disconnected all cables at the Vapor Container (VC) blisters, inside and outside the VC, except for those cables which are required to support activities within the VC,
- DWP/VCA-02A 1996 Miscellaneous VC Removals His DWP im olved removal of Containment Ventitation Fans (FN-10-2 and 4) VC Ventilation and '
Purge System ductwork, miscellaneous equipment, piping / tubing components and structural steel.
The DWP Structure / Systems / Components (SSCs) are located above and below the " broadway" platform area and outside the Bio-Shield wall of the Vapor Container (VC).
He VC Purge Supply and Ring ducts and Fans located outside the Biological Shield Wall were removed as part of this DWP and temporary flexible ducting installed to provide VC heating / cooling / ventilation during Decommissioning actisities as required.
- DWP/WDBA-01 Waste Disposal Building Clean-Out His DWP removed all of the remaining mechanical and electrical components from the Waste Disposal Building. ;
1 The mechanical and electrical systems removed by this DWP are listed below:
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e . Liquid Waste Processing Subsystem i e Component Cooling Water System (now connected to Service Water System) j e Service Water System o Heating System ;
e Compressed Air System 1 e . Liquid Waste Effluent System l
- MCC-5 )
e Waste Disposal Control Board e Lighting Panels, Distribution Panels & Misc. Electrical Hardware The equipment removed and identified in this DWP provided various functions during plant operation. With an alternate waste water treatment system in place, this equipment had no functional requirements. He equipment identified in the scope of this DWP was classified as Non-Nuclear Safety.
- DWP/WT-01 Water Treatment Facility Removal l-This DWP removed equipment from the Water Treatment facility including all tanks, pumps, i
valves and the associated piping, instrumentation, electrical components, wiring and conduit. The Water Treatment facility is no longer in use. l The following systems were removed by this DWP:
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.* Portions of Service Water
- Portions of Compressed Air e Condensate inside water treatment
- Portions of Heating & Ventilation
- Chemical Feed i e Portions ofInstrument Air The Water Treatment Facility was classified as non-nuclear safety and is not required for the safe storage of spent fuel at YNPS. The facility produced demineralized water for use in the primary and secondary systems at YNPS during plant operations. Since shutdown, demineralized water ,
was supplied with a mobile water treatment unit that was brought to the plant whenever water !
inventory was low.
C. Temporary Chances a TCR/96-09 Fire System Pressure Maintenance Safety Evaluation I
The purpose of this TCR was to use the condenser tube cleaning pump (P-77) to maintain pressure l I
of the fire system during the period of time the normal pressure maintenance system was out of service. A check valve was installed on FS-V-738, the strainer flush valve for the Auxiliary Boiler Room Sprinkler system. A hose ran from the discharge of P-77 to FS-V-738. FS-V-674, the Turbine Building Sprinkler Systems strainer drain, was throttled, to maintain system pressure greater than 100 psig to prevent the diesel fire pump from starting to maintain system pressure and to insure flow through the P-77 to prevent overheating the pump. )
l D. NNS Channes I a NNS/95-004-Construction Power Feed Installation-RCA NNS Modification 95-004 provided the guidance for installation of construction Motor Control Centers CMCC-A and CMCC-B. The construction provided power for selected plant loads which are currently supplied by MCC4 Bus I and 2 and MCC5 Bus I and 2.
The construction MCC's have been installed to remove the loads which must remain energized during decommissioning activities.
- NNS/95-005-Vapor Container Construction Feed The design change relocated the power supplies for the following equip r cm .ocated in the Vapor Container: Vent Fans and their associated louvers, Polar Crane CR-2,480 V Power Receptacles, Distribution Panels including the Jib Crane, Instrumentation /Gaitronics. In addition, this modification included the installation of temporary and emergency lighting in the Vapor Container.
In order to facilitate the decontamination and removal of the equipment located in the Vapor Container, the minimum required equipment need for the decommissioning has been powered from a single powered source defined as a " construction feed". This NNS modification will allow the disconnection of permanent power sources for equipment inside the Vapor Container.
- NNS/95-006 Spent Fuel Pool (SFP) Island This modification has provided a dedicated electrical power supply and Electrical Distribution 7
1 System for the SFP facility. This has isolated the SFP from the remainder of the plant Electrical
. Distribution System and allowed the decommissioning process to continue without electrically affecting the SFP.
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l E. Other Channes a Safety Evaluation - Change to Procedure on Release of Materials This safety evaluation modified the plant procedure for release of materials by (1) clarifying which l materials would be surveyed prior to leaving the site, (2) clarifying the survey methods used and expanding the description of typical instrumentation, and (31 clarifying the release methods used I when surveying large or bulk quantities of materials with a low probability of being contammated l by describing the sampling process and aggregate surveys which are performed. These changes are consistent with the release protocol presented in NRC Circular No. 81-07, Control of radioactive Material, and NRC Information Notice No. 85-92, Surveys of Wastes Before Disposal From i Nuclear Reactor Facilities, as well as the guidance in Draft NUREG/CR-5849, Manual of Conducting Radiological Surveys in Support of License Termination.
l These changes simply clarified the types of radiological surveys that may be used to release l
materials from the Radiological Controlled Area or the YNPS site. The surveys have no impact on i decommissioning activities or spent fuel handling.
- Safety Evaluation - Change to Final Status Survey Plan For the purposes of Final Status Survey, this safety evaluatica modified and expanded the site ;
classification definitions of agccred and rmagected areas and provided a proceduralized !
I classification methodology based on radiation survey results and historical reviews. This modification is based upon the experienced obtained through additional sampling and analyses i since the submittal of the YNPS Decommissioning Plan and through industry decommissioning i experience at Fort St.Vrain and Shoreham.
' This modification is administrative in nature and only impacts the frequency of the final status survey in those areas not expected to be contaminated. The modification has no impact on spent fuel storage or movement of spent fuel.
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